Adenosine-assisted neurovascular surgery: initial case series and review of literature

Cerebral aneurysms in complex anatomical locations and intraoperative rupture of aneurysms are challenging for neurosurgeons and anaesthetists alike. Mechanical and non-mechanical methods to reduce blood flow into aneurysms are well-recognised techniques to facilitate aneurysm exclusion from the circulation. Mechanical methods like temporary clipping of parent arteries, carotid artery ligation and endovascular balloon occlusion are commonly used in clinical practice. However, non-mechanical techniques such as rapid ventricular pacing and adenosine-induced cardiac standstill with hypotension are still emerging strategies. The aim of this study is to report our units' experience in the use of adenosine in aneurysm clipping and arteriovenous malformation (AVM) resection and review the literature. The records of all patients who had adenosine-assisted clipping of intracranial aneurysms and AVM resections in our institute between November 2015 and December 2016 were extracted from prospectively maintained database. The following data were collected: patient demographics, comorbidities, size and location of the aneurysms or AVM, number of boluses and total dose of adenosine administered, duration of cardiac standstill and hypotension (systolic blood pressure < 60 mmHg), intraoperative and postoperative complications and outcome scores at discharge. Literature search on Embase and PubMed for the terms "adenosine and clipping", "adenosine and aneurysm" and "adenosine and AVM" was performed. Eight aneurysms and two AVMs were identified. While both AVMs were elective procedures, half of the aneurysm clippings were on urgent basis. We used adenosine safely with spontaneous return of rhythm in all cases. Temporary clips to the parent artery were applied for brief periods in 2 patients who had pre-adenosine intraoperative rupture. We did not observe any immediate or late adverse events related to administration of adenosine. From our literature review, a total of ten case series and four case reports were identified. There were no reports on the use of adenosine in AVM resection. Transient adenosine-induced asystole is a safe and effective technique in facilitating surgical treatment of complex aneurysms and AVMs. In addition, adenosine use reduces the need, duration, and associated complications of temporary clip applications to parent arteries.